I don't understand these 450 bugdet builds.. Just have some patience wait sometime and save some money. Why throw 450$ on a system when u could wait a few months and play your games on high-ultra settings with a way better build??
Even if you have the money sometimes it is hard to justify throwing a ton at a computer. It just doesn't appeal to some folks.
Much like cars. Some people will go do all kinds of custom exhaust and what-not on a car, but really even if most folks have the money they aren't going to toss money at that kind of thing for their car. It doesn't appeal to them.
I paid around $450 without OS for my about a year ago to my recollection.
All new parts I got an 8GB Corsair Vengeance Ram, i3-2100, Sapphire 6850 GPU, H61 Motherboard, DVD Drive, CX430 PSU, NZXT Gamma, and a 500GB Seagate Drive. I would say $450 can get you a plenty decent gaming build.
If you are going for just gaming you could drop the CPU down and pick up a 7850 and have a build that would handle a lot of games quite nicely.